This is a Kyrielle, written about the artwork for Joy Division’s 1979 debut album ‘Unknown Pleasures’. This image represents a stacked plot of the radio signals from the first observed pulsar – CP1919. A pulsar is a rapidly rotating neutron star that emits pulses of radio waves at regular intervals as the star rotates, much like a lighthouse beam sweeping across the night sky. Similarly, a stacked plot is simply a regular line graph that has been subdivided into its various components, so that the comparisons between these components, as well as the totals can be seen.